A large part of Manchester Airport was evacuated this afternoon after a man attempted to carry an unidentified white powder onto a plane. The substance was discovered in a bag that the Asian MUSLIM man, who was planning to take on a flight from Manchester to London Heathrow.

It comes as Britain’s terror level was increased to ‘severe’ last night, meaning an attack is ‘highly likely’. The rest of the airport remains open, but a number of flights have been delayed.

A chemical incident was declared and the check-in and security screening areas at the airport’s Terminal 3 were evacuated. It is understood he told airport staff that he was carrying a ‘freeze-dried compound’ on behalf of a friend.

A Greater Manchester Police spokesman said: ‘Shortly before 12.55pm, police at Manchester Airport were called by security staff from the check-in desk at Terminal 3, who had discovered a non-identified white powder in a bag which a man was attempting to carry on to a plane.

‘Officers attended along with the fire service and they declared it a chemical incident. ‘Tests are currently on-going to establish what the powder is.

Intelligence sources said the decision followed a ‘non-specific’ warning from the CIA that the UK is facing an increased threat from Al Qaeda. It is thought the Home Office’s decision to increase the terror alert level last night was prompted by the impending visit by Hilary Clinton. Professor Richard Bonney believes the arrival of the U.S. Secretary of State in London next week is why the official level has gone from substantial to severe. Home Secretary Alan Johnson announced the shift last night. The new level denotes that an attack is ‘highly likely’ and is the second highest on a five-step scale.

Mr Johnson said last night: ‘The Joint Terrorism Analysis Centre has today raised the threat to the UK from international terrorism from substantial to severe. ‘This means that a terrorist attack is highly likely, but I should stress that there is no intelligence to suggest that an attack is imminent. UK DAILY MAIL